Luminescent tube



Sept. 4, 1923.

F. J. METZGER LUMINESCENT TUBE Filed Aug. 6. 1921 INVENTOR A TTORNE VSPatented Sept. 4, 1923.

UNITED STATES 1,467,187 PATENT OFFICE.

FLOYD J. METZGER, OF NEW YORK, N. Y., ASSIGNOR TO AIR REDUCTION COMIPANY, INCORPORATED, A CORPORATION OF NEW YORK.

LU'mmEscEN'r TUBE.

Application filed August a, 1921. Serial No. 490,428.

New York, in the county of New ork,

State of New York, have invented certain.

new and useful Improvements in Luminescent Tubes; and Ido hereby declarethe following to be a full, clear, and exact description of theinvention, such as will enable others skilled in the art to which itappertains to make and use the same.

This invention relates to luminescent tubes wherein an electricaldischarge passes through an atmosphere preferably rarefied 1 andconsisting, for example, of neon, helium or other gaseous medium whichis thereby caused to glow.

Such tubes have been made heretofore with electrodes disposed therein orwith conductive coatings disposed either internally or externally uponthe Walls of the tube. Electrodes are relatively unsatisfactory owing tothe frequent breakage of the connecting wire resulting from vibration ofthe 2 electrodes.

nated by supporting the tube by means of glass beads or the like but atadditional expense. Metallic or other conducting coatings are moresatisfactory though difficult to apply uniformly and relativelyexpensive. a

It is the object of. the present invention to simplify and cheapen themanufacture of luminescent tubes and to provide at the same time-a moresatisfactory and durable conducting medium in the tubes which are thusmore readily available for general signaling purposes for which they areotherwise well adapted.

Further objects and advantages of the invention will be apparent as. itis better understood by reference to the following specification andaccompanying drawing, in Which- Fig. 1 is a view in elevation of aluminescent tube embodying the invention.

Fig. 2 is a longitudinal section through one end of the tube, and

Fig. 3 is a section on Fig.2.

In conducting extensive studies of luminescent tubes containing neon,for example, it has been discovered that metal woool, e. g., ordinarilysteel wool, may be employed adthe line 3-3 of of metal coating,

This difficulty is in part elim 1- I the electrodes within example,

vantageously to provide the conducting medium at the ends of such tubes.Preferably the metal wool is sealed within the ends of the tube and isconnected to metallic conductors which pass through the ends of thetube. The metal wool, being relatively light, andsupported by contactwith the walls of the tube, does not vibrate when the tube is subjectedto shock so that there is no,

danger of breaking the electrical connection. It furmshes, moreover, anextended dispersion surface which ensures the'maximum discharge throughthe tube. By the use of metal wool, the costof manufacture of tubes isgreatly reduced because it may be readily inserted in the ends of thetube before sealing. The difiiculties attending the depositelectrolytically or otherwise, uniformly on the. interior surface of thetubes is thus avoided.

Preferably the plugs of metal wool are formed, prior to insertion in thetubes, over a thimble or core so that they are hollow. This increasesthe amount of discharge surface exposed and consequently the efficiencyof. the conducting medium, though tubes may be satisfactorily made withplugs of metal wool which are not cored. In either case, the conductorswhich pass through the wall of the tube are preferably bent andentangled in the metal wool so that disengagement is prevented.

Referring to the drawing, 5 indicates the tube which may be straight orof any suitable form' and dimensions. It may be shaped in the outlinesofletters or symbols for signalling purposes or in arbitrary'outlines I.of steel or other metal wool and conductors 8 are sealed through theend walls and are bent as at 9 and entangled in the metal wool, Ashereinbefore noted, the plugs may be provided with central hollow spaces10 extending substantially therethrough.

When such a tube is filled with neon, for at a suitable pressure, e. g.,five to fifty millimeters of mercury, and the conductors are connectedto a source of high tension electrical current, the tube'will glow witha reddish-orange light. If other gases are used, the character and colorof the light emitted will vary.

It will be observed that an advantage lies in the peculiar simplicity ofthe invention and particularly in the ease with which tubes can beassembled by relatively unskilled labor. The tubes are, moreover,durable and eflicient, the metal wool being substantially unaffected bythe passage of the current because heat generated is dispersed throughthe wall of the tube without subjecting it to excessive temperature,because the numerous threads of the metal wool contact with the wall atmany points.

Various changes and modifications may be made within the scope of theaccompanying claims without departing from the invention or sacrificingany of the advantages thereof.

I claim:

1. A luminescent tube wherein an electrical discharge passes betweenconducting surfaces, the surfaces comprising metal Wool disposed in theends of the tube and conductors sealed through the wall of the tube andengaging the metal wool.

2. A luminescent tube wherein an electrical discharge passes betweenconductin surfaces, comprising metal wool disposed in the ends of thetube and arranged adjacent the wall thereof with a hollow central spaceand conductors sealed through the wall of the tube and engaging themetal wool.

luminescent tube wherein an electrical discharge passes betweenconducting surfaces, the surfaces comprising metal wool disposed in theends of the tube and conductors sealed through the wall of the tube andentangled with themetal wool.

4. A luminescent tube wherein an electrical discharge passes betweenconducting surfaces, the surfaces comprising steel Wool disposed. in theends of the tube and conductors sealed through the wall of the tube andengaging the metal wool.

5, Aluminescent tube having conducting surfaces consisting of metal wooldisposed at its ends.

In testimony whereof I aflix In FLOYD J.

signature.

TZGER.

